04376309 is referenced by 39 patents and cites 11 patents.

An improvement in tracking the signal-eyes (FIG. 4) formed by a digital signal is disclosed. This improvement is achieved by forming a sample at a regeneration sampling time (e.g., 404), a first sampling time (e.g., 401) and a second sampling time (e.g., 402). The first and second sampling times respectively precede and succeed the signal-eyes while each regeneration sampling time occurs within the signal-eyes. The amplitude of each sample represents the amplitude of the digital signal at the sampling time relative to a reference level (e.g., 301, 302 or 303) which passes through one of the signal-eyes. A first comparison signal is generated by comparing the amplitudes of the samples at the regeneration and adjacent first sampling times. Similarly, a second comparison signal is generated by comparing the amplitudes of the samples at the regeneration and adjacent second sampling times. The difference between the first and second comparison signal is then averaged to form an error signal. The error signal varies with movement of the signal-eyes relative to the regeneration sampling time. In one embodiment (FIG. 2) of the invention, this error signal is used to align the regeneration sampling time with a predetermined position within the signal-eyes.

Title
Method and apparatus for signal-eye tracking in digital transmission systems
Application Number
6/268274
Publication Number
4376309
Application Date
May 29, 1981
Publication Date
March 8, 1983
Inventor
Mitchell A Skinner
Seabrook
NH, US
Gerald L Fenderson
Newton
NH, US
Agent
David R Padnes
Assignee
Bell Telephone Laboratories Incorporated
NJ, US
IPC
H04L 7/04
View Original Source